The apparatus and method disclosed herein is an improvement in the technique of integrated finishing and compressive preshrinking of fabric. Representative of one such technique is the apparatus and method presented in U.S. Pat. No. 4,031,596. In the mentioned patent, an integrated finishing and compressive preshrinking range is disclosed wherein fabric having a relatively high moisture content by weight is first subjected to a finishing step wherein greige goods is treated with the usual finishing additives, thence partially dried to approximately 15% moisture content by weight, and is thereafter directly preshrunk in a conventional rubber belt preshrinking unit. The essential novelty of this integrated system resides in the greater uniformity of preshrinking which occurs when fabric is only partially dried from a fully moistened condition before passing through the preshrinking unit; as compared with fully drying the fabric, storing and remoistening of the fabric to a 15% moisture content level prior to preshrinking.
In the prior integrated system, after the finishing operation, which involves the application of finishing additives in a water solution by passing fabric through a padder, the excess moisture is removed by squeezing the fabric between padder rolls. The amount of moisture removed is necessarily a function of the pressure which can be reasonably applied without distortion of the fibers in the fabric. In any event, the amount of moisture retained by the fabric is about 80%-100% by weight.
The present invention concerns the integration of finishing and compressive preshrinking steps wherein precise moisture control intermediate the two steps is achieved particularly to optimize fabric straightening. It has been found in particular instances where straightening devices are used that at least a minimum optimum moisture content level is necessary for the straightening apparatus to be fully effective. For example, in tests which have been run for denim fabric, the straightening apparatus is optimally effective at moisture content levels of at least 30% or greater. Since there is no advantage to achieving moisture content levels beyond 50%, and in fact there is a detriment in additionally moistening the fabric to such levels because of the wasteful expenditure of energy and additional capital equipment needed to subsequently dry the fabric to the 15% moisture content level, it is very important that moisture applied to the fabric be precisely controlled so that only the optimum moisture content level is achieved.
It is the purpose of the present invention to describe a stepwise moistening arrangement which precisely can apply any percentage of moisture to fabric prior to straightening, subsequent drying and preshrinking.